Photoshop CS6 periodically freezes on my iMac running 10.9.5. It did the same thing on 10.9.4. I tried uninstalling and reinstalling; this did not help. I don't use any plug-ins and haven't modified Preferences. When it freezes, there is no error message, but I cannot move the main Photoshop window, nor can I click on any buttons or move sliders or use any of the options in panels. Curiously, I can pull down menus in the top menu bar (File, Edit, Image, etc.) but since these menu options open dialog boxes that are not functional, I'm pretty much dead-in-the-water.
If I open the Force Quit Applications window (Cmd-Option-Esc), Photoshop looks like it is running normally, i.e. it doesn't say "Not Responding". If I Force Quit anyway and restart, Photoshop behaves normally for a while (time varies) and then freezes again.
This behavior does not seem to be associated with any particular action or command that I can discern. If I don't Force Quit, then Photoshop eventually recovers on its own and starts working normally for awhile before freezing again. Anyone have suggestions for corrective steps?